Ray tracing particle image velocimetry – Challenges in the application to a packed bed

Ray tracing Particle Image Velocimetry (RT-PIV) is an optical technique for high resolution velocity measurements in challenging systems, such as transparent packed beds, that uses ray to correct distortions introduced by geometries the light paths. The based correction a post processing step applied raw PIV particle images before classical evaluation. In this study, RT-PIV performed top layer of body centred cubic (bcc) sphere packing with gaseous flow, where access obtained use N-BK7 glass balls diameter d=40 mm. introduces new experimental and numerical challenges, example limited field view, illumination difficulties, very large required depth sensitivity geometric parameters used correction. These challenges their implications are main scope discussed present work. Further, validation reconstruction presented examples corrected vector fields bed given. results show strength method reconstructing behind spheres would not have been accessible measurement techniques without